The invention lies in the field of spinning and relates to a spinning machine having a plurality of spinning stations for spinning fiber material into a yarn. The invention further relates to a spinning arrangement with such a spinning machine.
Conventional spinning machines for producing yarns of staple fiber material usually comprise a plurality of spinning places, e.g. two by fifty spinning places, which are arranged in two rows. Every spinning place is supplied with the fiber material in the form of a longitudinal object (e.g. sliver, slubbing or roving yarn) usually from a respective container (can) or from a bobbin and a yarn is formed in the spinning place from the supplied fiber material.
The actual yarn formation occurs for example by ring spinning, can spinning, cap spinning, friction spinning, rotor open-end spinning, air-vortex spinning, etc., with each spinning place comprising the apparatus parts required for the yarn formation and for winding up the formed yarn. Such apparatus parts of all spinning places are usually driven by way of a common driven or a small number of common drives and can be disconnected from said drive for individual spinning places (yarn breakage, change of can).
Prior to the actual yarn formation, the supplied longitudinal object of the fiber material is refined in the spinning machine by drafting or opening for example. For such refining the spinning machine comprises refining means, i.e. means for drafting such longitudinal objects or means for opening such longitudinal objects. The refining means are usually provided jointly for all spinning places or for a number of spinning places, as are the means for yarn formation for each spinning place. A single central drive or a small number of individual drives is provided for driving the refining means, as is also commonly applied for the yarn formation, which drives each assume a driving function for the refining means. It is also known to use separate small drives for each spinning place or even in each spinning place for each drive function.
Means for refining prior to yarn formation by drafting the supplied longitudinal fiber object are provided for example with three pairs of cylinders disposed in series which are driven in the direction of conveyance with increasing circumferential speed. Such pairs of cylinders extend for example along a row of spinning places and are driven for example by way of respective gears by a single drive or one separate drive is provided for each pair of cylinders (drive function). Within the terms of the aforementioned refining means which are driven internally in the spinning places, the publication DE-3932614 (Murata Kikai) describes drafting arrangements for each spinning place with a plurality of drives, which drafting arrangements can be adjusted individually. This allows producing different yarns on one and the same spinning machine and, optionally, individually adapting the drafting process to fine spinning-place-internal differences.
Means for refining the yarn formation by opening the supplied longitudinal fiber objects are provided for each spinning place for example with a feed roller, an opening roller and a fiber guide conduit leading the fibers in the opened state from the opening roller to the yarn formation zone. The entirety of the feed rollers and the entirety of the opening rollers are each driven by a common drive for example.
The yarns formed in the individual spinning places are monitored for example online or periodically by sensors and spinning places which perform poorly are disconnected from common drives. The disconnection can relate to the yarn formation or additionally also to the refining which is positioned upstream of the yarn formation.
It is also known to monitor the yarn formation (e.g. in the air-vortex spinning method) at each spinning place online or by periodic measurements and to individually regulate or adjust the machine parts which are used for yarn formation during the spinning process. Such regulations or adjustments relate to the supply of air to the spinning jet or the speed of the take-off rollers which are disposed downstream of the spinning jets. Respective methods and apparatuses are described for example in the publications EP-0289010 (Rieter) or EP-0365931 (Schubert and Salzer).
High requirements are placed on yarns which are produced with the spinning machines as briefly described above, especially their evenness concerning fiber mass per unit of length. According to the state of the art, these high requirements are fulfilled in such a way that the longitudinal fiber objects, before they are supplied to the spinning machine, are evened out to a very high degree in an evening process which particularly comprises several successive cycles of mixing and drafting. This ensures that the longitudinal objects as supplied to the spinning places already meet the requirements placed on evenness and that as a result it is sufficient to substantially keep the refining and spinning parameters constant during the spinning process and especially in each spinning place.
For the evening of the fiber material prior to spinning, a plurality of so-called autoleveller draw frames are used in which a plurality of incoming longitudinal fiber objects (e.g. from the carding machine or from the upstream autoleveller draw frame) are mixed and the fiber mixture is drawn. In order to even out the fiber mass per unit of length, the drafting ratio is controlled or regulated on the basis of mass measurements at the entrance and/or exit of the autoleveller draw frame, which occurs in such a way that the speed of at least one pair of cylinders in the drafting arrangement is changed. Such autoleveller draw frames receive the longitudinal fiber object from storage containers (cans) and supply the produced longitudinal fiber object again to storage containers from which the longitudinal fiber objects are finally supplied to a spinning machine or a spinning place. The management of such storage containers is very laborious, especially when the same is to be performed fully automatically. Without automation or with only partial automation, the management of the storage containers is work intensive and susceptible to errors.
It is an object of the present invention to provide a spinning machine which can produce yarns of high evenness concerning fiber mass per unit of length, even though the fiber material supplied to the spinning places is provided with a lower such evenness than would be required for known spinning machines for the same yarn quality. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The spinning machine in accordance with the invention, which like the known spinning machine, comprises a plurality of spinning places arranged in such a way that the refining step (e.g. drawing or opening) for each spinning place, which is provided upstream of the effective yarn formation, is controlled and/or regulated on the basis of measured data as determined at the same spinning place concerning fiber mass per unit of length. For this purpose, the spinning machine in accordance with the invention is provided for each spinning place with sensor means for detecting at least one property correlating with the fiber mass per unit of length of the supplied fiber material and/or the produced yarn, as well as refining means which are controlled and/or regulated specific to each spinning place at least partly on the basis of the measured data detected by the sensor means. Optionally, the yarn formation which is provided downstream of the refining is also controlled or regulated specifically to each spinning place.
In such an equipped spinning machine, it is possible to perform directly and continuously at least a part of the evening concerning fiber mass per unit of length in each spinning place, so that at least a part of the evening steps which are performed discontinuously according to the state of the art (with the help of cans or bobbins) can be omitted. Optionally, it is even possible to omit discontinuously performed evening steps completely, thus making a completely continuously performable spinning process potentially feasible.
When the longitudinal fiber objects are supplied directly to the spinning places of the spinning machine in accordance with the invention within the terms of a continuous spinning process and when, between upstream apparatuses and spinning places which supply the longitudinal fiber object there are provided regions with free slack of the longitudinal fiber objects as a buffer, it is also possible, within certain limits which are predetermined by the spinning method and by the arrangement of the spinning place, to adapt the output of the individual spinning places to the filling level of the buffers or to output of the upstream apparatus. For this purpose, a spinning place is controlled in its entirety for an increase or decrease of its output. A buffer storage means which is known from the publication WO-99/1 1847 and connects a carding machine and an autoleveller draw frame for example can be adapted accordingly as a buffer storage means for a direct connection of an apparatus supplying a longitudinal fiber object and a buffer storage means of a spinning place of the spinning machine as to be provided in accordance with the invention.
A further advantage of the spinning machine in accordance with the invention is that for the start spinning (after a yarn breakage or change of can) refining means and, optionally, the yarn formation means can run through a start spinning cycle which is completely independent from other spinning places and in which the speeds of moved parts increase continuously for example. As a result, start spinning becomes considerably easier than in machines according to the state of the art in which moved parts can be coupled merely with a drive running with constant speed, which leads to a step-like or at least very steep increase of the respective speeds.
In the simplest of cases, sensor means of the spinning machine according to the invention detect for each spinning place the fiber mass in the zone of the entrance of the refining means and the inflow speed to the refining means is respectively varied by a respective control of the refining means. Further control methods which are also applicable are known from autoleveller draw frames or carding machines and are usually realized as closed loop control with a measuring element disposed downstream of the actuating element and/or as open loop control with a measuring element disposed upstream of the actuating element. Usually the closed loop control is used to compensate relatively long-wave fluctuations and the open loop control is used to compensate relatively short-wave fluctuations.
In order to compensate any irregularities or fluctuations in the fiber mass as detected by the sensor means, the draft of the fiber mass is essentially varied in the spinning place, which occurs in such a way that the inflow speed of the fiber mass into the spinning place and/or the outflow speed of the yarn from the spinning place is respectively controlled or regulated.
In the case of an inflow control, the longitudinal fiber objects are preferably supplied to the spinning places from cans or from bobbins, so that apparatuses which supply the longitudinal fiber objects are not influenced by fluctuations of the inflow speed into the spinning place.
The yarn formation means must also be provided with a controllable arrangement for an outflow control in addition to the refining means. This is possible within wide margins and with a relatively high speed especially for air-vortex spinning methods, for which the yarn properties are independent within relatively wide margins from the spinning speed and in which no large masses need to be accelerated or braked for a change in the spinning speed (small inertia). Such air-vortex spinning can be false twisting or at least partly real twisting (so-called vortex spinning methods) and are usually performed with the help of a spinneret and a pair of take-off rollers. The fiber twisting is produced by the spinneret by a fluid supplied to the nozzle. The pair of take-off rollers and the fluid supply must be controlled accordingly to produce a change in the spinning speed and/or spinning draft. An air-vortex spinning method which is particularly suitable for a spinning-place-internal outflow closed-loop control is described for example in the Swiss patent application 1845/00 (application date: Sep. 22, 2000).
Ring spinning, open-end, and friction spinning methods are not so suitable for the aforementioned outflow closed-loop control, because for these methods the yarn properties are independent from the spinning speed in only narrow margins. A wider margin in which the yarn properties are independent from the spinning speed is offered by the can spinning method. This method is not very suitable, however, for an outflow closed-loop control due to the relatively large rotating masses.
Known open-loop and closed-loop control methods for evening fiber masses which are designed for autoleveller draw frames or carding machines can be applied to refining means of individual spinning places of the spinning machine in accordance with the invention and the machine parts required for this purpose can easily be adapted to the application in accordance with the invention by a man skilled in the art. Such open-loop and closed control methods are described for example in the following publications: WO-99/66113 (Rieter, autoleveller draw frame), EP-176661 (Zellweger, autoleveller draw frame), U.S. Pat. No. 4,864,694 or U.S. Pat. No. 4,506,414 (Zinser, autoleveller draw frame), EP-340756 (TrUtzschler, autoleveller draw frame), EP-649923 (Howa, autoleveller draw frame), DE-3703450 and DE-3703449 (Trxc3xctzschler, carding machine).
Embodiments of the spinning machine according to the invention which are shown as examples are described in detail in the schematic figures below. All figures only show one spinning place each of the spinning machine. The entire spinning machine is provided with a plurality of such spinning places which are arranged in at least one row.
The figures show: